"The highest temperature on record in the United States during the month of June is 129 in Death Valley, California, on June 30, 2013. That record could be in jeopardy this weekend and early next week."
And it's not just the deserts boasting intolerable heat, Accuweather reports that Palm Springs, Phoenix, and Las Vegas should "approach their all-time record-high temperatures" during the heatwave, with peak heat expected on Monday. In general, the southwestern region is looking at temperatures 10 - 20 degrees above average.
To stay safe during the heatwave, drink lots of water, wear light-colored clothing, and make sure to take breaks during physical activity. Another good tip is to head to the beach, where temperatures will be 30 - 40 degrees cooler.